Electrical trans former



(No Model.)

R E. THOMSON.

ELECTRICAL TRANSFORMER.

"No. 508,650. Patented Nov..14, 1893.

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UNKTED TATES PATENT @rricn.

ELIIIU THOMSON, OF SWVAMPSCOTT, MASSACHUSETTS, ASSIGNOR TO THETHOMSON-HOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

ELECTRICAL TRANSFORMER.

SPECIFICATION forming part of Letters Patent 1\lo. 508,650, datedNovember 14, 1893. Application filedAugust 28.1891. Serialllo.403,954(NoniodeL) T at whom it may concern:

Be it known that I, ELIHU THOMSON, a citizen of the United States,residing at Swampsoott, in the county of Essex and StateofMassachusetts, have invented certain new and useful Improvements inTransformers, of which the following is a specification.

The present invention relates to the construction of transformers foroperation with alternating currents. Such transformers may be employedfor the conversion of very high potential into low potential currents,or the reverse.

My invention relates to such transformers as may be inclosed in oil ormay be placed in air, as desired. Someof myimprovements are well adaptedto the construction of very large transformers, or to transformers ofhigh capacity.

My improvements consist in specialarrangements in relation to retainingthe insulation of the primary coils and for carrying olf heat from thesame.

In the accompanying drawings Figure 1 is a sectional view of' one formof'transformer. Fig. 2 is a side view of the same. Figs. 3 and 4 aresimilar views of a modified form.

Fig. 1 shows a transformer embodying cer tain of my improvements andplaced in a surrounding case B, which may be filled with oil. The ironcore M, M of the transformer surrounds the primary and secondary coilsP, P and S, and is of the usual laminated structure, as indicated inFig. 2and is supported in the caseby suitable stops or wedges V,V, V,holding it firmly in position. The coarse wire coil S, S, which may bethe secondary or primary as desired, is shown wound around the centralsection of the core M but effectually insulated from the same. The finewire coil which may be the primary, is constructed in sections P, P?with an insulating plate I? sepa rating the sections, while anotherinsulating plate I, I, I, separates it effectually from the coil S, S.The manner of winding the coil sections P and P is that the layers arepreferably placed on a slant, shown by the shading, so that theterminals of the coils are as far apart as possible, and so that thesuccessive portions of the coils, as it were, progress outwardly fromthe middleor junction of the two sections shown tothe terminals a, I),thus giving the terminals the{ greatest possible separation one from theother,while theinterposed plate I ,which maybe of mica, glass, or otherexcellent non-conductor, prevents the possibility of leakage from onesection to the other. All around the coil sections P, P are spaces, f,provided for receiving the insulating atmosphere or insulating mediumsurrounding the coils and preserving their insulation, or to put itdifferently, these spaces are provided for removing the metal of theiron core M progressively from the coil sections P, P as the differenceof potential of the turns or layers rises. Hence the arrangement isadapted to the use of the very highest potentials in the coils P, P.

The arrangement shown in Figs. 3 and at is adapted to very largetransformers. Here the insulating plate which separates the two coils ismade very thick so as not to be liable to perforation. Both sets ofcoils are wound in sections, as S to S and P to P with open spacesbetween for the circulation of the oil or other fluid which insulatesthem and the connections of the sections are alternately at the outerand inner portions of the sections. At the end sections of the higherpotential coils, as P to P are air spaces e,f, of considerabledimensions, allowing the thorough insulation of the end sections orthose which possess the highest potential. At Pis an insulating pieceinserted to sustain the sections in place, and at the same time to fillthe space between the core M and the coil sections. To this end thepiece I is notched to receive the coils and for the better circulationof the medium surrounding the coils is perforated with a series ofholes. 7

The whole transformer Fig. 3, may when constructed, beimmersed in a casecontaining oil or insulating fluid as before. Separating pieces ofglass, porcelain or other good insulating material may be insertedbetween the coil sections wherever needed to retain them in theirrelative positions.

What I claim as new, and desire to secure by Letters Patent, is

1. A transformer comprising primary and secondary coils in inductiverelation, one of such coils being divided into two portions connectedtogether at their more central portions, and the layers of which slantaway from each other so as to progressively separate the windings astheir difierence of potential increases.

2. A coil or Winding for high tension currents, divided into twoportions connected together at theirinnercentral portions, and thelayers of which slant away from one another as described,the windingsbeing progressively separated as their difference of potentialincreases.

3. A coil or winding for high tension currents divided into two portionsseparated by an insulating plate and connected together at their innercentral portions, and the layers of which slant away from one another asdescribed,the windingsheing progressivelyseparated as theirdifierence ofpotential increases.

at. A transformer comprising primary and secondary coils and a coreentering and surrounding such coils, and having its coil surroundingportion separated from the coil a distance depending on the potential ofthe adjacent portion of the coil.

5. In a transformer, a core surrounding the coils and having its severalportions separated different distances from the adjacent portions of thecoils, in accordance with the differences of potential existing betweensuch portions of the core and coils.

6. A transformer having a core surrounding its coils, an inclosing casecontaining oil in which the coils are immersed, and insulated perforatedretaining pieces for such coils, as and for the purpose set forth.

In witness whereof I have hereunto set my hand this 25th day of August,1891.

ELII-IU THOMSON.

Witnesses:

JOHN W. GIBBONEY, BENJAMIN B. HULL.

